Silicone endotracheal tubes broke during tracheal extubation of two dogs after uneventful anaesthesia. The remaining pieces were removed via endoscopy, and both dogs recovered with no further problems. A third silicone endotracheal tube broke while checking for cracks prior to its use. Biofilm formation on the surface of the endotracheal tube is thought to be the main cause of the breakage. Destruction of the biofilm is difficult, therefore exhaustive cleaning with detergents followed by vigorous brushing is recommended to break the interaction between the silicone surface and the biofilm. It is suggested that careful attention is paid to how tubes are cleaned and dried (in a hanging position), and that they are checked carefully for cracks prior to each use.

This retrospective study aimed to identify the most accurate formula for estimating the increase in packed cell volume (PCV) after whole blood transfusion of cats, as several formulae have been reported but not validated. Forty cats, of varying breeds and gender, were included from two referral institutions after database searches over a 13 year period. Five formulae were used to calculate an estimated post-transfusion PCV based on the re-working of formulae for determining the volume of donor blood to be transfused; three formulae were derived from those previously reported in the feline literature and two from human paediatric medicine, where a similar mean blood volume has been described. Cats were subdivided into two groups, the first consisting of 17 cats with non-regenerative anaemia and the second consisting of 23 cats with ongoing losses such as haemolysis and haemorrhage; it was hypothesised that formulae could be more accurate for group 1 cats, whereas formulae applied to group 2 cats could have overestimated the post-transfusion PCV. Bland-Altman analysis was performed for all cats to compare the actual increase in PCV with the calculated increase for the five formulae. Formula 1 (PCV % increase = volume of blood transfused in ml/2 × bodyweight in kg) performed best overall and is easy to calculate; however, no single formula was highly accurate at predicting the PCV increase after whole blood transfusion in cats and, owing to the wide confidence intervals, these formulae should be applied judiciously in the clinical setting.

Case summary A 9-year-old neutered female British Shorthair cat (case 1) and a 13-year-old neutered male domestic shorthair cat (case 2) showed signs of chronic T3–L3 myelopathy, which progressed over 6 and 12 months, respectively. On presentation, case 1 had moderate pelvic limb proprioceptive ataxia and ambulatory paraparesis, and case 2 was non-ambulatory paraparetic and had urinary incontinence. Bilateral enlargement of the articular process joints at T11–T12 in case 1 and T3–T4 in case 2 causing dorsolateral extradural spinal cord compression was shown on MRI. Surgical decompression by a unilateral approach through hemilaminectomy with partial osteotomy of the spinous process was performed in both cases. The side of the approach was chosen based on the severity of the cord compression. Surgery resulted in a satisfactory outcome with short hospitalisation times. On discharge, case 1 showed mild postural reaction deficits on both pelvic limbs. Case 2 had regained urinary continence and could ambulate unassisted, although it remained severely ataxic. The 6 month follow-up showed very mild paraparesis and proprioceptive ataxia in both cats. No chronic medical treatment was required. Relevance and novel information This is the first report to describe clinical presentation, imaging features, surgical treatment and outcomes of thoracic vertebral canal stenosis owing to bilateral articular process hypertrophy in cats with no adjacent spinal diseases. Thoracic articular process hypertrophy should be included in the differential diagnosis of adult cats with chronic progressive myelopathy. Hemilaminectomy with partial osteotomy of the spinous process might be an appropriate surgical technique in these cases.

Optic neuritis (ON) is a recognized condition, yet factors influencing recovery of vision are currently unknown. The purpose of this study was to identify prognostic factors for recovery of vision in canine ON of unknown etiology. Clinical databases of three referral hospitals were searched for dogs with presumptive ON based on clinicopathologic, MRI/CT, and fundoscopic findings. Twenty-six dogs diagnosed with presumptive ON of unknown etiology, isolated (I-ON) and MUE-associated (MUE-ON), were included in the study. Their medical records were reviewed retrospectively, and the association of complete recovery of vision with signalment, clinicopathologic findings, and treatment was investigated. Datasets were tested for normality using the D'Agostino and Shapiro-Wilk tests. Individual datasets were compared using the Chi-squared test, Fisher's exact test, and the Mann-Whitney U-test. For multiple comparisons with parametric datasets, the one-way analysis of variance (ANOVA) was performed, and for non-parametric datasets, the Kruskal-Wallis test was performed to test for independence. For all data, averages are expressed as median with interquartile range and significance set at p < 0.05. Twenty-six dogs met the inclusion criteria. Median follow-up was 230 days (range 21–1901 days, mean 496 days). Six dogs (23%) achieved complete recovery and 20 dogs (77%) incomplete or no recovery of vision. The presence of a reactive pupillary light reflex (p = 0.013), the absence of fundoscopic lesions (p = 0.0006), a younger age (p = 0.038), and a lower cerebrospinal fluid (CSF) total nucleated cell count (TNCC) (p = 0.022) were statistically associated with complete recovery of vision. Dogs with I-ON were significantly younger (p = 0.046) and had lower CSF TNCC (p = 0.030) compared to the MUE-ON group. This study identified prognostic factors that may influence complete recovery of vision in dogs with ON. A larger cohort of dogs is required to determine whether these findings are robust and whether additional parameters aid accurate prognosis for recovery of vision in canine ON.